The initiatives — 12 to date ranging from no-contract postpaid plans to affordable unlimited data — have disrupted the mobile industry and added millions of subscribers to the Magenta Carrier’s ranks.

The event will mark T-Mobile’s first formal return to the trade show since CES 2014, when Legere revealed Un-carrier 4.0 (an offer to pay off new subscribers’ early-termination fees), and was famously ejected from an AT&T developer party he crashed with chief financial officer Braxton Carter.

This go-round, Legere is planning to announce his latest enticement on the first day of CES (Jan. 5), and has been teasing the event via videos on Twitter and YouTube:

But amid all the hoopla, the company’s customer-first credo is being called into question by Change To Win (CtW), a labor union confederation that claims the carrier is putting undue pressure on its store staff to sell. In a complaint filed with the Consumer Financial Protection Bureau, the group said sales goals are so high and penalties for falling short so harsh that some associates and managers have taken to adding unauthorized services to customers’ accounts.

In an online poll of over 2,200 T-Mo customers conducted by CtW across five states in July, 36 percent said they were signed up for higher-cost services like phone insurance, additional lines, and unlimited data or texting without their consent.

It’s not the first time customers have been caught by surprise: Two years ago the carrier settled a Federal Trade Commission (FTC) lawsuit by agreeing to pay at least $90 million in refunds and $22.5 million in fines and penalties after billing customers for unwanted third-party services like horoscopes, love tips and celebrity gossip in a practice known as “cramming.”